Spin-orbit interaction (SOI) plays a key role in creating Majorana zero modes in semiconductor
nanowires proximity coupled to a superconductor. We track the evolution of the induced superconducting
gap in InSb nanowires coupled to a NbTiN superconductor in a large range of magnetic field strengths
and orientations. Based on realistic simulations of our devices, we reveal SOI with a strength of
0.15–0.35 eV Å. Our approach identifies the direction of the spin-orbit field, which is strongly affected by
the superconductor geometry and electrostatic gates.